I've submitted the following bug report directly to Godzilab. I encourage other players who are having the same issues to also submit a report so that the issue is seen as widespread (every player I've talked to who has a large enough cave is dealing with it):
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"Dear Godzi Lab,
I wanted to submit a formal bug report, since I know you are busy working on more content for the game and do not see every discussion on Touch Arcade and Mojo Farm.
Currently, when a player expands the cave a fourth time, the refresh-rate for iron and mushrooms doubles. I have tested this several times over the last few days and confirmed it with other high level players on touch arcade.
So, to be clear, if a player has expanded their cave 1, 2, or 3 times, then resources replenish approximately every 1hr45min period. If a player expands four or more times, then the they must wait twice as long for mushrooms and iron to respawn. My cave has been expanded five times, and it takes 3hrs and 30 minutes for a full refresh.
To put things in even more concrete terms, a player whose cave has been expanded five times is losing about 90 iron to this bug every day, and cannot generate more iron per day than players who have only expanded three times.
I hope I have described the bug clearly. Please let me know if you have any further questions, and thank you for your time and consideration.
-JRJ "
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